JPH04355736A - Device for warning emission of strobe light for camera - Google Patents

Abstract

PURPOSE:To provide a device for warning the emission of strobe light and capable of preventing the occurrence of vignetting. CONSTITUTION:The device is constituted of an accessory attachment/detachment detecting means 13 for detecting the attachment/detachment of an accessory 21, a detecting means for generating focal distance information concerning a lens and information concerning an object distance, and a warning means for judging whether or not the vignetting occurs based on the outputs from the former detecting means and the latter detecting means and for warning, or inhibiting the emission of the strobe light. Thus, warning and inhibiting the emission of the strobe light are outputted in accordance with the occurrence of the vignetting when a long-sized lens is attached with a camera main body, or when a hood 21 is attached to the leading end of the lens, so that the risk of photographing a picture in a state where the vignetting occurs can be eliminated.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a strobe light warning device applied to a camera with an interchangeable lens and built-in strobe.

0002

2. Description of the Related Art Conventionally, cameras with built-in strobes have been known as single-lens reflex cameras. This known camera with a built-in strobe has a display function to notify that charging for strobe light emission is completed or incomplete as a warning means, and a warning display function to notify that strobe light does not reach the subject. Additionally, devices have been proposed that have a function that warns or prohibits use if the photographic lens blocks the strobe light.

0003

[Problems to be Solved by the Invention] However, in conventional cameras with a built-in strobe, the strobe light does not get vignetted just by attaching the lens, but if an accessory such as a hood is attached to the tip of the lens, the strobe light will not be vignetted as shown in Figure 8. The light L may be vignetted by the lens attachment 103, and the vignetting may be reflected on the screen. FIG. 8 is a diagram illustrating the vignetting state, where 101 is the camera body and 101a is a strobe light emitting unit. Reference numeral 102 indicates a lens attached to the camera, and reference numeral 103 indicates an accessory attached to the lens. FIG. 9 shows a state in which the shadow K1 of the accessory is projected on the screen at that time, and the shaded area is the vignetting range. Generally, in order to reduce the aforementioned vignetting, it is necessary to raise the position of the built-in flash of the camera, but raising the position of the built-in flash goes against the trend of making cameras more compact. Yes, but not desirable.

In addition, with conventional cameras with built-in strobes, when a lens is attached (for example, a zoom lens), there is no vignetting on the screen if the camera is at the telephoto end or the subject distance is a certain distance, but if the camera is at the wide-angle end or the subject distance is close, the strobe will not vignetting. Vignetting may occur due to the light lens. However, in the conventional example, it is only necessary to determine whether the strobe light is vignetted for each lens, so even in the case of a zoom lens, it was necessary to choose either a lens that causes vignetting or a lens that does not.

FIG. 10 shows a state in which the strobe light L is vignetted. As shown in the figure, the strobe light L is on lens 1.
02 causes vignetting, and as shown in FIG. 11, the vignetting is reflected on the screen, resulting in a photograph with a lens shadow K2 on the screen. To prevent such vignetting,
As mentioned above, it is necessary to raise the position of the built-in strobe and shorten the overall length of the lens 102, but raising the position of the built-in strobe leads to making the camera larger and also makes the lens 102 shorter. Shortening the overall length will lead to a reduction in optical performance, so neither of these measures can be taken in terms of camera design.

SUMMARY OF THE INVENTION An object of the present invention is to provide a strobe light warning device configured to prevent vignetting without changing the dimensions of conventional cameras and lenses.

[0007]

[Means for Solving the Problems] The strobe light warning device of the present invention is provided with attachment/detachment detection means for detecting attachment/detachment of an accessory such as a hood attached to the lens and outputting attachment/detachment detection information. The lens or camera is provided with a warning means that warns or prohibits flash emission when the strobe is emitted based on attachment/detachment detection information, prompting the user to remove the accessory or use an external strobe, and both means. It is characterized by being composed of.

In another strobe light warning device of the present invention, a lens is provided with a detection means for detecting a focal length and a subject distance, and vignetting of the strobe light caused by the lens occurs on the screen based on the output information of the detection means. Determine whether
The present invention is characterized in that the lens or the camera is provided with a warning means for prompting the user to use an external strobe by giving a warning if it is determined that vignetting will occur, and that the camera is constituted by both means.

[0009]

[Embodiments] Examples of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of an interchangeable lens according to a first embodiment of the present invention. Reference numeral 1 designates a fixed barrel that supports a first group lens barrel and a group lens barrel, which will be described later, and has rollers inserted therein and straight grooves 1b and 1c cut therein for allowing the first group lens barrel and second group lens barrel to move straight. Furthermore, a bayonet groove 1a is formed for attaching a hood, which will be described later. 2 is a first group lens barrel that supports a first group lens 4. 3 is a second group lens barrel that supports a second group lens 5. 4 is a first group lens whose focal length is variable by movement, and 5 is a second group lens which is focused by movement. Reference numeral 6 denotes a zoom operation ring that rotates with respect to the fixed barrel 1, and is provided with a cam groove that engages with a roller 8 attached to the first group barrel 2 to move the first group barrel 2 back and forth. 7 is a cam ring rotatable with respect to the fixed barrel 1, and has a cam groove that moves the second group barrel 3 back and forth by engagement with a roller 9 attached to the second group barrel 3;
It has a gear part that meshes with the gear of the motor 10. Reference numeral 8 denotes a roller that is attached to the first lens barrel 2 and enters the linear groove of the fixed barrel 1 and the cam groove of the zoom operation ring 6. Reference numeral 9 denotes a roller that is attached to the second group lens barrel 3 and enters the linear groove of the fixed barrel 1 and the cam groove of the cam ring 7. Reference numeral 10 denotes a motor, which has a gear 10a that meshes with a gear portion of the cam ring 7. 11 is a rear cover attached to the fixed barrel 1, and 12 is a mount attached to the rear cover 11 for mechanically connecting the lens to the camera. 13 is a detachment detection switch (hereinafter referred to as SW), which is attached to the fixed tube,
It is composed of a first contact piece 13a and a second contact piece 13b having a protrusion projecting from a part of the bayonet groove of the fixed cylinder 1 described above. 14 is a flexible printed circuit board electrically connected to the attachment/detachment detection SW 13, and 15 is an electrical contact fixed to the mount 12 and electrically connected to the camera side. 1
A main board 6 is electrically connected to the motor 10, the flexible printed circuit board 14, and the electrical contacts 15, and is equipped with an electric circuit including a microcomputer that controls the motor drive, the output of lens information to the camera, and the processing of information from the camera side. ing.

FIG. 2 is a diagram showing details of the operating state of the above-mentioned attachment/detachment detection SW 13, and FIG. 2(a) shows a state in which no accessories are attached to the lens. At this time, the first contact piece 13
The contact pieces a are urged toward the second contact piece 13b and are in contact with each other, the contact pieces 13a and 13b are electrically connected, and the attachment/detachment detection SW is turned on. FIG. 2(b) shows a state in which accessories are attached to the lens. Reference numeral 21 designates a hood as an accessory, and a bayonet claw 21a is bayonet-engaged with a bayonet groove of the fixed barrel 1. At this time, the first contact piece 13a is pushed inward by the bayonet claw 21a of the hood 21,
The first contact piece 13a and the second contact piece 13b are electrically insulated,
The attachment/detachment detection switch 13 is turned off. The above contact piece 13
The connection and insulation of a and 13b are input to the microcomputer on the main board 16 via the flexible printed circuit board 14,
The information is further output to the camera side via the electrical contact 15.

Next, the operation of the camera to which the above-mentioned accessory attachment/detachment detection information is input will be explained with reference to the flowchart of FIG. When SW1 is turned on, a signal is sent to the lens to perform autofocus (AF). After the autofocus is completed, photometry is performed and a photometry value is calculated. Then, when the strobe light emission selection SW is OFF, AV and TV are determined based on the above-mentioned photometric values, and when SW2 is turned ON, exposure control is performed to the AV and TV determined as described above, and shooting is completed. . If SW2 is OFF, the process returns to before photometry.

On the other hand, when the strobe light emission selection switch is ON, it is determined that light emission is selected, and the exposure control is set to the strobe light emission mode, and AV and TV are determined to be constant values regardless of the photometric value. Then, it is determined whether the charging required for strobe light emission is completed, and if it is not completed, it is charged until the charging is completed.
Alternatively, a warning and a light emission prohibition are performed until the light emission selection SW is turned OFF. After charging is completed, if the accessory attachment/detachment detection SW 13 is OFF based on the lens information, a warning is given that an accessory is attached to the lens. In addition, attachment/detachment detection SW13
If is ON, it is determined that no accessories are attached to the lens, and no warning is issued. Then, when SW2 is turned on, the AV and TV are controlled to the previously determined values, and at the same time, strobe light is emitted, and the light emission is stopped based on the dimming of the light, completing the photographing. When SW2 is OFF, the process returns to before photometry.

FIG. 4 is a flowchart showing a second embodiment of the present invention. When SW1 is turned on, a signal is sent to the lens to perform autofocus. After the autofocus is completed, photometry is performed and a photometry value is calculated. and,
When the strobe light emission selection SW is OFF, AV and TV are determined based on the photometric values described above, and when SW2 is turned ON, exposure control is performed to the AV and TV determined as described above, and photographing is completed. Moreover, when SW2 is OFF, the process returns to before photometry.

On the other hand, when the strobe light emission selection switch is ON, it is assumed that light emission is selected, and the exposure control is set to the strobe light emission mode, and AV and TV are determined to constant values regardless of the photometric value. Then, it is determined whether or not the charging necessary for strobe light emission is completed, and if it is not completed, a warning and light emission prohibition are performed until the charging is completed or the light emission selection switch is turned OFF. After charging is completed, based on the lens information, if the accessory attachment/removal detection switch is OFF, it is assumed that the accessory is attached to the lens, and the accessory is removed or the light emitting selection switch is turned OFF.
Warnings and flash prohibition until F is reached. When the attach/remove detection SW is ON, it is determined that no accessory is attached to the lens and no warning is given. When SW2 is ON, the AV and TV are controlled according to the previously determined value, and at the same time the strobe light is turned on. emits light, and the light emission is stopped based on the dimming of the light, completing the shooting. Moreover, when SW2 is OFF, the process returns to before photometry.

FIG. 5 is a sectional view of a lens according to a third embodiment of the present invention. As mentioned above, reference numeral 1 is a fixed barrel that supports the first group lens barrel and the second group lens barrel, and has a straight groove cut therein for allowing the first group lens barrel and the second group lens barrel to move straight through rollers 8 and 9. 2 is a first group lens barrel that supports a first group lens 4. 3 is a second group lens barrel that supports a second group lens 5. 4 is a first group lens whose focal length is variable by movement, and 5 is a second group lens which is focused by movement. Reference numeral 6 denotes a zoom operation ring that rotates with respect to the fixed barrel 1, and has a cam groove cut into it that engages with a roller 8 attached to the first group barrel 2 to move the first group barrel 2 back and forth. 7 is a cam ring rotatable relative to the fixed cylinder;
The second group lens barrel 3 engages with the roller 9 attached to the second group lens barrel 3.
It has a cam groove that moves the motor back and forth, and a gear part that meshes with the gear of the motor 10. A roller 8 is attached to the first group lens barrel and enters the linear groove of the fixed barrel 1 and a cam groove of the zoom operation ring 6. A roller 7 is attached to the second group barrel 3 and fits between the linear groove of the fixed barrel 1 and the cam ring 7. This is the roller that goes into the cam groove. Reference numeral 10 denotes a motor, which has a gear 10a that meshes with a gear portion of the cam ring 7. 11 is a cover after being attached to the fixed tube; 1
2 is a mount attached to the rear cover 11 to mechanically connect this lens to the camera; 17 is a zoom brush fixed to the first group barrel 2; and 18 is a focus fixed to the second group barrel 3. 19 is a flexible substrate having a code pattern for detecting the movement of the zoom brush 17 and focus brush 18; 15 is an electrical contact fixed to the mount 12 and electrically connected to the camera side; , is. 16 is motor 1
0, the flexible substrate 19, and the electrical contacts 15, and is equipped with an electric circuit including a microcomputer that controls motor drive, output of lens information to the camera, and processing of information from the camera side.

Next, the operation of the lens will be explained using FIG. When the photographer rotates the zoom operation ring 6 to change the focal length, the roller 8 moves along the cam groove of the zoom operation ring 6 and the linear groove of the fixed barrel 1, and as a result, the first group lens 4
zooms back and forth. At the same time, the zoom brush 17 also moves on the code pattern of the flexible substrate 19 and outputs zoom information. On the other hand, when focusing, motor 10
The rotation causes the cam ring 7 to rotate, and the rollers 9 move along the cam groove of the cam ring 7 and the rectilinear groove of the fixed barrel 1, so that the second lens group 5 moves back and forth to perform focusing. At the same time, the focusing brush 18 also moves on the code pattern of the flexible substrate 19 and outputs focus information. Then, the output zoom and focus information is stored on the main board 1.
The signal is input to the microcomputer 9, processed, and transmitted to the camera side through the electrical contact 15.

FIG. 6 is a block diagram showing the apparatus of this embodiment. Focal length information and object distance information are processed in a lens information output section within the microcomputer and output to the camera side via electrical contacts. . Each piece of information is compared in size with a predetermined value in a comparison circuit within the camera, and the information is input to a determination circuit. If it is determined that the focal length f and subject distance S are smaller than the predetermined values, a warning device is activated. The camera sends a signal to the camera and issues a warning indicating vignetting of the strobe light.

Next, referring to FIG. 7, the operation of the camera will be explained using a flowchart. When SW1 is turned on, a signal is sent to the lens to perform autofocus. After the autofocus is completed, photometry is performed and a photometry value is calculated. Then, when the strobe light emission selection SW is OFF, AV and TV are determined based on the above-mentioned photometric values, and the SW is turned off.
2 is turned on, the AV and TV determined as described above
Exposure is controlled to achieve the value of , and the shooting is completed. In addition,
If SW2 is OFF, the process returns to before photometry.

On the other hand, when the strobe light emission selection SW is ON, it is assumed that light emission is selected, and the exposure control is set to the strobe light emission mode, and AV and TV are determined to be constant values regardless of the photometric value. Then, it is determined whether the charging necessary for strobe light emission is completed, and if it is not completed, a warning is issued until the charge is completed or the light emission selection switch is turned OFF. After charging is complete,
Based on the lens information, the focal length f and the subject S are compared with predetermined values (here, f0, S0), and the focal length f,
If both of the objects S are smaller than a predetermined value, a warning is given. Then, when SW2 is turned on, the AV and TV are controlled to the previously determined values, and at the same time, strobe light is emitted, and the light emission is stopped based on the dimming of the light, completing the photographing. Moreover, if SW2 is OFF, the process returns to before photometry.

Note that in the above-mentioned embodiment, when it is determined that the lens light is vignetted, the light emission is not prohibited even if a warning is given, but if f and S are smaller than the predetermined values, the light emission is not prohibited until the photometry. It is also possible to go back and prohibit strobe light emission.

[0022]

[Effects of the Invention] As explained above, in the device of the present invention, the lens is provided with a means for detecting attachment/detachment of accessories to the lens, and based on the detection signal, a warning is issued or a prohibition of strobe emission is issued. We encouraged users to remove accessories or use an external strobe.
Even in a compact single-lens reflex camera with a built-in strobe, there is no fear of vignetting of strobe light caused by accessories on the screen, and it is possible to prevent the occurrence of failed photographs due to user carelessness or lack of knowledge regarding cameras.

Furthermore, in the apparatus of the present invention, the lens is provided with a detection means for detecting the focal length and the subject distance, and it is determined based on the two pieces of information whether or not vignetting of the strobe light caused by the lens occurs on the screen. Since a warning is given to prompt the user to use an external strobe, it is possible to prevent screen vignetting caused by the lens, which has been a problem in conventional single-lens reflex cameras with a built-in strobe.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view of an interchangeable lens equipped with a strobe light warning device according to a first embodiment of the present invention.

2(a) is a diagram showing an ON state of an accessory attachment/detachment detection switch provided on the interchangeable lens of FIG. 1, and FIG. 2(b) is a diagram showing an OFF state of the switch.

FIG. 3 is a flowchart of camera control operations including operations of a strobe light warning device mounted on the interchangeable lens of FIG. 1;

FIG. 4 is a flowchart of a camera control operation having a function partially different from that shown in FIG. 3;

FIG. 5 is a vertical sectional view of an interchangeable lens equipped with a strobe light warning device according to a second embodiment of the present invention.

6 is a diagram showing the configuration of a strobe light warning device configured using the interchangeable lens shown in FIG. 5. FIG.

7 is a flowchart of a control operation of the camera having the configuration shown in FIGS. 5 and 6. FIG.

FIG. 8 is a diagram showing a state of vignetting caused by a conventional single-lens reflex camera with a built-in strobe when a hood 103 is attached as an accessory to perform strobe photography.

FIG. 9 is a diagram showing a photographing screen of a photograph taken in the state shown in FIG. 8;

FIG. 10 is a diagram showing the occurrence of vignetting of strobe light due to the lens 102 when performing strobe photography with a conventional single-lens reflex camera with a built-in strobe.

FIG. 11 is a diagram showing a photographing screen of a photograph taken with a strobe in the state shown in FIG. 10;

[Explanation of symbols]

1...Fixed tube
2...First group barrel 3...Second group barrel
4...First group lens 5...Second group lens
6...Zoom operation ring 7
...cam ring
8, 9...Roll 10...Motor
10a...Gear 11...Rear cover
12...Mount 13...Attachment/detachment detection switch 14, 19...Flexible printed circuit board 15...Electrical contact
16... Main board 17... Zoom brush
18... Focusing brush 21... Hood
21a...bayonet claw

Claims (4)

[Claims] Claim 1: A strobe light emission warning device equipped on a camera, which comprises a camera body with a built-in strobe device, and an interchangeable lens attached to the camera body, wherein the interchangeable lens is provided with a hood, etc. Attachment/removal detection means for detecting whether an item is attached, and warning means for at least one of issuing a warning against strobe light emission or prohibiting strobe light emission based on an output signal of the accessory attachment/removal detection means. A strobe light warning device for a camera, comprising: 2. A strobe light emission warning device according to claim 1, wherein said accessory attachment/detachment detection means is provided on said interchangeable lens. 3. A strobe light emission warning device installed in a camera, comprising a camera body with a built-in strobe device and an interchangeable lens attached to the camera body, the interchangeable lens being configured to It has a detection means for detecting the distance or both, and determines the amount of vignetting of the strobe light caused by the lens based on at least one of focal length information and subject distance information detected by the means, and based on the determination result. 1. A strobe light emission warning device for a camera, comprising warning means for issuing a warning against strobe light emission or prohibiting strobe light emission. 4. A strobe light emission warning device according to claim 3, wherein said detection means is provided on said interchangeable lens.